Tumors & Tumors & PseudotumorsPseudotumors of the Perinephric of the Perinephric SpaceSpace

Srinivasa R PrasadSrinivasa R Prasad

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Perinephric Space: IntroductionPerinephric Space: Introduction

• Inverted cone shaped space between 2 renal fasciae• Formed during embryonic ascent of the kidneys• Intercommunicating space that opens into the pelvis• Abuts the bare area of the liver & subphrenic space • Contains the kidneys, adrenals, & proximal ureters

Solitary soft tissue mass in the Solitary soft tissue mass in the perirenalperirenal spacespace

• Most lethal urological Ca; 30% of patients manifest metastases; 50% of patients die within 5 years

• 200,000 annual new cases worldwide; 13,000 annual deaths in the US

• >125% increase in incidence in the US (1950)• Heterogeneous disease with variable histo-biology• RCC: >90% of kidney masses; most common

perirenal mass

PerirenalPerirenal mass: Renal Cell Carcinomamass: Renal Cell Carcinoma

* * JemalJemal A et al. CA Cancer J A et al. CA Cancer J ClinClin 20042004

2004 WHO Taxonomy of RCC

* * EbleEble JN et al. WHO Handbook 2004JN et al. WHO Handbook 2004

Histology (%) of RCCs

Putative Cell of Origin

Clear Cell RCC 70 Proximal convoluted tubular epithelium

Papillary RCC 15 Proximal convoluted tubular epithelium

ChromophobeRCC

5 Cortical collecting duct; Type B intercalated cell

Hereditary Cancer Syndrome

5

Renal Renal LeiomyomaLeiomyoma

• Rare, benign renal mesenchymal neoplasm• Mostly capsular origin; less commonly renal pelvis• Uniform solid tumor; exophytic/peripheral location• Hypervascular tumor supplied by capsular vessels

• Most common retroperitoneal soft tissue sarcoma• 15% of MFHs occur in the retroperitoneum• Large heterogeneous mass that displaces the kidney

Malignant fibrous Malignant fibrous histiocytomahistiocytoma

HemangiomaHemangioma

• Rare mesenchymal retroperitoneal neoplasm• Renal hemangioma may extend to perirenal space

– Arise from medulla or renal sinus• T2-bright mass with persistent enhancement on MR• Soft tissue mass with characteristic phleboliths

Multiple Multiple perirenalperirenal space soft tissue massesspace soft tissue masses

PerirenalPerirenal MetastasesMetastases

• Lung/breast Ca, melanoma may rarely involve perirenal space

• Lung Ca: Proclivity due to connections between perirenal & mediastinal lymphatics

• Multiple soft tissue nodules around the kidneys

RindRind--like like perirenalperirenal space massspace mass

PerirenalPerirenal LymphomaLymphoma

• Usually contiguous spread from retroperitoneal dz• B-cell NHL > common in retroperitoneum/kidney • Isolated perirenal dz in <10% of pts; Hodgkin dz• Multiple masses; diffuse-infiltrative; rind-like mass• Compress kidney without affecting function

Retroperitoneal fibrosisRetroperitoneal fibrosis

• Isolated or multisytem idiopathic fibrosing disorder• Autoimmune disorders such as AIP, scleroderma• Usually encases aorta, IVC & ureters; perirenal rare• Stage-specific imaging findings: inflammatory

tissue or fibrosis; MR more specific than CT

ErdheimErdheim Chester diseaseChester disease

• Idiopathic systemic non–Langerhans cell histiocytosis• Skeletal & systemic manifestations more common• Rind-like perirenal/periureteral soft-tissue masses• Severe kidney compression may lead to CRF

PerirenalPerirenal space mass with macroscopic fatspace mass with macroscopic fat

AngiomyolipmaAngiomyolipma

• Now classified as PEComas; sporadic or inherited• Tuberous sclerosis complex (B/L, multiple AMLs)• Life threatening hemorrhage (AMLs > 4cm), CRF• Uncommon triphasic renal mesenchymal neoplasm

– Dysmorphic vessels, fat & smooth muscle (soft tissue)– Lipid-poor in <5% patients; indistinguishable from RCC

PerirenalPerirenal liposarcomaliposarcoma

• Liposarcoma: most common retroperitoneal sarcoma• 6th-7th decades; frequently large at presentation• Variable biology & rates of recurrence/metastases• Variable fat, soft tissue & cystic components

– Well diff: >fat; myxoid: cystic; round cell: soft tissue

ExtramedullaryExtramedullary hematopoiesishematopoiesis

• EMH occurs in hemoglobinopathies/MP disorders• Liver, spleen, paravertebral areas: Embryonic

hematopoietic regions• Perirenal soft tissue masses with macroscopic fat

PerirenalPerirenal myelolipomamyelolipoma

• Rare, benign monoclonal tumors with fat/marrow• Commonly adrenal; extra-adrenal: perirenal/presacral• Predominant fatty mass; variable soft tissue content

PerinephricPerinephric space masses: Summaryspace masses: Summary

• Wide spectrum of masses; may be renal or RP in origin• Isolated disease or part of systemic syndrome• Classified based on origin, distribution & morphology• Some tumors have characteristic imaging findings• Histopath exam after biopsy: definitive diagnosis• Accurate diagnosis: optimal patient management

PerinephricPerinephric space masses: Referencesspace masses: References• Surabhi V, et al. Neoplastic and Non-neoplastic Proliferative Disorders

of the Perirenal Space: Cross-sectional Imaging Findings. RG 2008• Gore RM, et al. The great escape: interfascial decompression planes of

the retroperitoneum. AJR 2000• Nagar AM, et al. Giant renal capsular leiomyoma: study of two cases.

Br J Radiol 2004 • Israel GM, et al. CT differentiation of large exophytic renal

angiomyolipomas and perirenal liposarcomas. AJR 2002• Wilbur AC, et al. Perirenal metastases from lung cancer: CT diagnosis.

J Comput Assist Tomogr 1992• Kumar M, et al. Bilateral extraadrenal perirenal myelolipomas: an

imaging challenge. AJR 2004